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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Ho Nieh nominated to the NRC
Nieh
President Trump recently nominated Ho Nieh for the role of commissioner in the Nuclear Regulatory Commission through the remainder of a term that will expire June 30, 2029.
Nieh has been the vice president of regulatory affairs at Southern Nuclear since 2021, though he is currently working as a loaned executive at the Institute of Nuclear Power Operations, where he has been for more than a year.
Nieh’s experience: Nieh started his career at the Knolls Atomic Power Laboratory, where he worked primarily as a nuclear plant engineer and contributed as a civilian instructor in the U.S. Navy’s Nuclear Power Program.
From there, he joined the NRC in 1997 as a project engineer. In more than 19 years of service at the organization, he served in a variety of key leadership roles, including division director of Reactor Projects, division director of Inspection and Regional Support, and director of the Office of Nuclear Reactor Regulation.
Dirk Wilhelm, Leonhard Meyer
Nuclear Technology | Volume 71 | Number 1 | October 1985 | Pages 162-172
Technical Paper | Nuclear Safety | doi.org/10.13182/NT85-A33717
Articles are hosted by Taylor and Francis Online.
The flow dynamics in the upper core structure (UCS) during the expansion phase of a liquid-metal fast breeder reactor core disruptive accident were investigated experimentally and numerically. A simulant material experiment was designed to verify some of the thermal-hydraulic models in SIMMER-II. The experiments showed the large effect of the heat transfer in the UCS and the relatively small effect of friction. The reduction of the work potential of the expanding fuel by the presence of the UCS is shown as a function of the initial pressure and the temperature difference between the core and the UCS, both for simulant materials and UO2 fuel. It is described how the experimental data can be extrapolated to prototypical conditions, which phenomena modeled in the code predictions of SIMMER-II are different for simulant and prototypical transients, and how the experimental results compare to effects of prototypical phenomena that could not be modeled in the experiment.
